Door latching mechanism



Aug. 21, 1945. J ABERNETHY 2,383,032

LAICHING IBCHANISI Filed Oct. 13, 2 Sheets-Sheet 1 INVENTOR.

Jo/m Abernathy ATTORNEY Patented Aug. 21, 1945 John Mmrnetliy, Bqrherton, Ohio assignor to The *Babcockfiz Wilox Coi'n'pany, Jersey City, N. J

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a ,gmm us "q i :4 Surroundminimum ,2; wd'QWinE a narmw a o r'r'idge 25 adapted to ng'age 5"s'ea1ing strip 28 g1. gshefitps an vthe like ,on the door frame [2 tor the puypoge pi meeting a ge s-tight closure of the A amrme 22, the recess s a nw d of t rim w mm qa ing a ui ab ira wr material 3! s fa; 'fi fictioxi'fdrvthe dog; ir -qflm. furnace heat. Ji s-T 2 and fsncw ,t eldqq n me my osed n sitian iniw i h is s m n h ld by. a vel t0rm9 =lathmmch i$m r ng a movab e 'la-tgh '32,. @iithe gravimy ac u t t p in engagement with" 5 statiqnqr'y' catch 34. ,Ihe a h 3Z-i$ mtall wsunmr edi 9n h door ammuwa be w qn-it Kin an n to ed PEI Q fih lat h pin 36.iavh ch ends hori zonall substanfiially parallel relation ,to the lan 91 en a em nt 9f. he 16.09. w h the fram 3 a p a iehe haqmnl qed nwar from e @2 5. Q1 djqq; m in it' being x g d r gqnvenience, of desicriptiqn as nthe'iplan'e oi sur-. 24m ang flte hc De 5 fin n a pmmml midw yi hqwflenl he inner sw m $3 p11 he. $1,99 flange 24 @na th pp n 's r a e 40 an the am fl n e'l- T e a ch i a he i rmq wi hea'dfii am; te end an m emu mm a: b ing b kq 4.5 i t ral w h 7119 .12 9 ',su ab 1- w d h he its an mw be' mu iad hya P lbe at h liis oxme .,a, eve tht lawn am" ll-M ne: side 9 "Wt; ni 6 'q w n Q1? lawn 29 3 1 fillfi fi l 54 1 Q h 51G the. n qt, nmcarr ng .th ll ndlq In thi embodiment the arm" 54' 'is enlargd 5,1? its 2mm rovide h9$ re-wea i airbd about the ri s mbl d the 'rqq Jam; sp ing h iin by nuts lifon the th eaded .qnp slteend fib r-9 't'o'irm the Qanlfifi; 1 2'1 1 j T e 1am bolt 52 1s i fill'e' hh 4 3 PIJ tion extending laterally and horizontally from the latch arm 50 in parallel relation to the latch pin 36, and in cross-section is somewhat elliptical in shape although in practice it may be formed as a rhomb with the corners normally formed at the interesctions of its fiat sides suitably rounded for smooth cooperation with certain surfaces on the catch which are engaged thereby. The elliptical cross-section is formed about major andminor axes arranged for example as indicated in Fig. 2, with the major axis, if extended, intersecting the longitudinal axis of the latch pin 36, and of a length approximately oneand-three-quarter times the length of the minor axis. Other suitable lengths of major axis may be utilized ranging approximately from one-andone-half to two times the length of the minor axis. The term elliptical, as used herein for convenience in defining such a shape, is to be interpreted as embracing not only a true ellipse but also such other rhomboidal shapes in approximation of an ellipse which will serve the same purpose.

The catch 34 provides a plurality of'latching positions, in this instance two, and in each of these positions the door is securely held against a force tending to swing the door outwardly, such as might result from an explosion of gas within the furnace. The catch has a keeper portion 66 formed as a depending hook having its tip 68 below the horizontal pivotal axis of the latch 32 as predetermined position of rest, the weight of the latch arm 54 and handle 56 overbalancing the weight of the latch arm 50 and bolt 52 and tending to rotate the latch clockwise beyond the position shown, a lug 90 however being formed on the door l0, preferably on the marginal wall or door flange 24, to provide a stop for the latch by engagement of the upper surface 92 of the latch arm 50 with the undersurface 94 of the lug to maintain the latch bolt 52 at the proper level for engagement with the sloping surface 80 of the catch as the door is being closed. The lug 80 'allows the latch arm 56 to rotate slightl beyond I the position normally occupied when the door is determined by the centerline of latch pin 36, a

unitary flange 70 being provided which by means of cap screws 12 enables the catch to be secured to the frame I2. The head of each screw 12 may be welded at a spot 14 to prevent the screw from loosening, or other suitable locking means may be utilized.

A narrow extension 16 on the catch, terminating in a nose 18 above the level of the latch pin 36, is formed with a forward camming surface 80 inclined upwardly at an angle preferabl less than 45 and slightly concaved throughout its extent from the tip 68 to the nose 18. In practice, it has been found desirable to provide an angularity of 28 from the horizontal for the camming surface 80 and a maximum concavity of about at the center.

The body of the hook or keeper portion 66 is formed with latching surfaces 82 and 84, these being in stepped relation for engagement by the latch bolt 52 for different positions to which the door may be swung in closing, the lower surface 82 being substantially vertical, and the upper surface 64 steeply inclined to the horizontal to within about 8 of thevertical, the transition from one latching surface to the other being gradual due to the reversely curved connecting surface 86, and a recess 88 being formed at the juncture of the adjoining surfaces 82 and 86.

When the door is fully closed, as illustrated in Figs. 1, 2 and 3, with the bead 26 in sealing contact with the packing strip 28, the latch bolt 52 is at the same level as the latch pin 36 with the major axis of its elliptical cross-section on a horizontal line intersecting the centerline of the latch pin 36. In this position, the centerline of the handle 56 is at an angle of about 10 from the vertical.

The door may be opened by an upward lift on the handle 56 whereupon the latch bolt 52 is released from engagement with the inclined latching surface 84 and rotated counter-clockwise to clear the tip 68 of the catch. Fig. 4 'sh'ows'the door in an open position with the latch 32 in a fully closed, a vertical clearance of about 1; inch being provided between the surfaces 92 and 94,

as indicated in Fig. 2, to enable the latch arm 56 to be rotated to a position where the bolt 52 is firmly wedged against the latching surface 84, without interference from the lug 90, while allowing for an additional amount of clockwise rotation to insure firm seating when the cooperating'surfaoes become worn or the packing 28 becomes compressed.

The door may be swung slowly to a closed position by exerting pressure against the door either with or without manipulation of the handle 56, whereupon the latch bolt 52 will ride downwardly along the forward camming surface 80 below the tip 68 into the first or safety latching position against the lower latching surface 82 within recess 88 and then into the second latching position against the upper latching surface 84, the handle 56 then being pressed down to clamp the door firmly against the packing 28.

However, it is more frequently desired to effect a quick closing of the door by slamming and this may readily be accomplished either by a light or heavy slam, provided sufficient force is applied by the operator to cause the door to be brought into contact with the frame as in the case of other free swinging doors with gravity-actuated latches. When the door is slammed, the sudden engagement of the latch bolt 52 with the camming surface 86 imparts a high rotational velocity to the latch 32 in a counterclockwise direction, away from the latching position, and unless there is prompt reversal of such movement and a high rotational velocity of the latch on the return, there is an opportunity for the door to rebound and move away from the frame to a position where the bolt 52 cannot engage either of the latching surfaces 82 and 84. The operation of closing the door would therefore have to be repeated, with the operator having to judge the degree of slam which will bring about the desired result.

According to the present invention the rotation of the latch is suitably timed in relation to the swing of the door so that latching is positive regardless of the degree of slam imparted to the door. For example, the latch arm 54 is provided with a projection 96 having a surface 98 inclined at about 135 to the major axis of the latch bolt 52, in offset relation to the central axis of the latch pin 36, and adapted to contact the vertical face I06 of the lug 90 at the limit of counterclockwise rotation of the latch 32, as illustrated in Fig. 5. In slamming the door, when the rounded end I02 of the latch bolt 52 strikes the forward camming surface of the catch, there is a rotation of the latch 32 at high velocity in a countercloclrwise direction which causes the projection 96 to impact the lug 96 with sufficient force to effect an immediate return of the latch at high velocity in a clockwise direction, the force due to gravity being supplemented to such an extent that. the latch bolt 52 will have been rotated to a level above the tip 68 of the catch, at a position rear.- wardly of the tip, before the door can move any appreciable distance away from the frame 12. The door 10 is thus automatically locked against outward movement by the bolt 52 coming to rest against either the lower latching surface 82 or the upper latching surface 84. The usual position of rest is the first or safety latched position, as shown in Fig. 6, where the rounded end I04 of the latch bolt is received within the recess 88 of the catch, and retained therein by the..over= balancing movement of the Weighted lever arm 54, in which position the door is spaced only a slight distance from its seat and may thereafter, at the convenience of the operator, be fully closed and sealed by a downward pressure 011 the handle 56. In the safety position the door is positively locked against opening even by application of a pry bar between the door and frame, although by a lift of the latch handle 56 the latch is easily disengaged for opening the door.

The impact surface I of the lug 90 is conveniently planar and substantially vertical so that, for the form shown, the latch moves through.

an angle slightly greater than 45 from its predetermined position of rest with the door open as in Fig. 4 to the position in which the projece tion 96 strikes the impact lug 90 as in Fig. 5, the

- angle of movement beyond 45 being due to the slight inclination of the major axis of the bolt 52 to the horizontal when in the position of Fig. 4. In the reverse direction, the angularity of travel need be only about to to return the bolt 52 to the safety position indicated in Fig. 6.

Figs. 7 and 8 show a latching mechanism similar to that already described but with modifications particularly applicable to doors of smaller size and weight. Parts of essentially the same form and function are designated by the same reference characters as in Figs. 1-6, except with primes, in order to facilitate comparison. The door I0 is swung relatively to the frame 2' to open and close the aperture 22, the door being sealed to the frame when fully closed by packin 28. Catch 34' is carried by the frame 12', and provides for a plurality of latching positions as in the previously described embodiment, with recess 88 adjacent the vertical surface 82 for holding the bolt 52 in a safety latching position, and with the steeply inclined surface 84' for holding the bolt in the final latching position.

The principal distinguishing feature of this arrangement is the form of latch H36 which provides a unitary handle portion I08 extending downwardly at approximately 135 from the major axis of the latch bolt 52', the projection 96 having its impact surface 98 inclined upwardly at approximately the same angle from the same axis. The handle is provided with a hole I I 0 adjacent its end to permit the use of a hooked tool for convenience in manipulating the latch, while a triangular rib I I2 projecting laterally from one side provides additional strength and suitable distribution of weight for satisfactory operation. The latch I06 may be mounted for pivotal oscillation on a latch pin H4 which is pinned within the bearing bracket 46' and fitted with a cotter pin H6 to prevent lateral displacement of the latch. In this form also, when the bolt 52' strikes the camming surface 85', the latch is suddenly rotated in a counterclockwise direction through approximately 45, whereupon impact of the pro-' jection 96 with the lug 90' causes immediate reversal of the latch rotationwith sufficient energy to snap the latch into one or the other of the latching positions before the recoil of the door occurs, the angularity of clockwise rotation being about 10 to 15 to throw the bolt 52 into the recess 88 for safety latching, or approximately 45 for contact with surface 84' with the door substantially closed and seated against packin 28.

The invention as herein disclosed in accordance with the provisions of the statutes will be understood by persons skilled in the art to be applicable in arrangements other than those specifically described, and to include features which may be used to advantage without a corresponding use of other features, within the scope of the appended claims.

I claim:

l. A latching mechanism for use with relatively movable parts, one of which constitutes a horizontally swinging door and the other a stationary frame for said door, said mechanism comprising a latch rotatable about a, horizontal axis fixed in relation to one of said parts, said latch having an integral bolt portion extending parallel to said axis for cooperation with a catch fixed in relation to the other of said parts, said catch having successive upright latching surfaces adapted to be separately engaged. by said bolt portion for positively holding said door in any one of a plurality of latched positions against a force tending to. swing said door in the opening direction, said latching surfaces being in stepped relation and forming a shouldered recess therebetween at a level below said axis, said latch being adapted for arrangement relative to said catch whereby application of a force to said latch to rotate said latch solely in on direction will cause said bolt portion to be moved from engagement with the lower of said latching surfaces within said recess into engagement with said latching surface above said recess while causing said door to be swung from partially closed to its fully closed position, said bolt portion being of rhombshaped cross section with respect to a major axis substantially in the plane of said rotational axis for engagement with each of said latching surfaces at one end of said major axis.

2. A latching mechanism for use with a horizontally swinging door and its stationary frame, said mechanism comprising a latch rotatable about a horizontal axis fixed in relation to said door parallel to its radius of swing, said latch having an integral bolt portion extending parallel to said axis for cooperation with a catch fixed in relation to said, frame, said catch having successive upright latching surfaces adapted to be separately engaged by said bolt portion for positively holding said door in any one of a plurality of latched positions against a force tending to swing said door in the opening direction, said latching surfaces being in stepped relation and forming a shouldered recess therebetween at a level below said axis, said latch being adapted for arrangement relative to said catch whereby application of a force to said latch to rotate said latch solely in one direction will cause said bolt portion to be moved from engagement with the lower of said latching surfaces within said recess into engagement with said latching surface above said recess while causing said door to be swung from a partially closed to its fully closed position, said bolt portion being of rhomb-shaped cross section with respect to a major axis substantially 'in the plane of said rotational axis for engagement with each of said latching surfaces at one end of said major axis.

3. A latching mechanism, for a horizontally swinging furnace door, adapted for positive latching operation when the door is slammed into its closed position, said mechanism comprising a lever form of latch adapted for mounting on said door for rotation about a horizontal axis, one end of said latch having a latch bolt of elliptical cross section projecting therefrom in parallel relation to said rotational axis for cooperation with a stationary catch, the major axis of said cross section lying substantially in the plane of said rotational axis, the opposite end of said latch being constructed and arranged to act as a counterweight tending to rotate said latch to a position where said latch bolt is above the level of said rotational axis, a stop on said door operative during the initial closing movement of said door for maintaining said major axis substantially horizontal to enable said latch bolt to engage a forwardly facing camming surface of said catch adjacent one end of said major axis, and means on said door angularly displaced from said stop for abruptly interrupting rotational movement of said latch resulting from forcible engagement of said bolt with said camming surface when said door is slammed, said means presenting a surface positioned for impact by said counterweight end for effecting reverse rotation of said latch at sufficient velocity to cause said latch bolt to operatively engage a rearwardly facing latching surface of said catch adjacent the opposite end of said major axis in time to substantially prevent opening movement of said door due to recoil.

4. A door latch of the gravity-actuated leverform type rotatable about a horizontal axis and adapted for positive latching operation when the door is slammed into its closed position, one end of said latch having a latch bolt of elliptical cross section projecting therefrom in parallel relation to said rotational axis for cooperation successively with upwardly diverging camming and latching surfaces of a stationary catch, the major axis of said cross section lying substantially in the plane of said rotational axis, the opposite end of said latch being constructed and arranged to act as a counterweight tending to rotate said latch to a position where said major axis is inclined upwardly from said rotational axis, said catch surfaces including rearwardly facing upright upper and lower latching surfaces horizontally offset to form a shouldered recess therebetween at a level below said rotational axis, an abutment means operative during the initial closing movement of the door for opposing said counterweight action whereby said major axis is maintained substantially horizontal to enable said latch bolt to engage a forwardly facing camming surface of said catch adjacent one end of said major axis, and a second abutment means angularly displaced from said first named means for abruptly interrupting rotational movement of said latch resulting from forcible engagement of said latch bolt with said camming surface when the door is slammed, said second abutment means functioning as an impact means supplementing gravitational forces for effecting rverse rotation of said latch at sufiicient velocity to cause said latch bolt to become seated within said shouldered recess adjacent the opposite end of said major axis substantially before recoil of the door takes place.

5. A door latch of the gravity-actuated leverform type rotatable about a horizontal axis and adapted for positive latching operation when the door is slammed into its closed position, one end of said latch having a latch bolt projecting therefrom in parallel relation to said rotational axis for cooperation successively with upwardly diverging camming and latching surfaces of a stationary catch, said latch bolt being cross-sectionally shaped substantially as a rhomb having rounded portions at opposite ends of its major axis, with said major axis substantially in a plane with said rotational axis and of a length one-andone-half to two times the length of the minor axis, the opposite end of said latch being constmcted and arranged to act as a counterweight tending to rotate said' latch to a position where said major axis is inclined upwardly from said rotational axis, said catch surfaces including rearwardly facing upright upper and lower latching surfaces horizontally ofiset to form a shouldered recess therebetween at a level below said rotational axis, an abutment means operative during the initial closing movement of the door for opposing said counterweight action whereby said major axis is maintained substantially horizontal to enable said latch bolt to engage a forwardly facing camming surface of said catch adjacent one end of said major axis, and a second abutment means angularly displaced from said first named means for abruptly interrupting rotational movement of said latch resulting from forcible engagement of said latch bolt with said camming surface when the door is slammed, said second abutment means functioning as in impact means supplementing gravitational forces for effecting reverse rotation of said latch at sufficient velocity to cause said latch bolt to become seated within said shouldered recess adjacent the opposite end of said major axis substantially before recoil of the door takes place.

JOHN ABERNETHY. 

